16201681 has 2 divisors, whose sum is σ = 16201682. Its totient is φ = 16201680.

The previous prime is 16201673. The next prime is 16201709. The reversal of 16201681 is 18610261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16072081 + 129600 = 4009^2 + 360^2 .

It is a cyclic number.

It is not a de Polignac number, because 16201681 - 2³ = 16201673 is a prime.

It is a super-2 number, since 2×16201681² = 524988934451522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16201621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8100840 + 8100841.

It is an arithmetic number, because the mean of its divisors is an integer number (8100841).

Almost surely, 2^16201681 is an apocalyptic number.

It is an amenable number.

16201681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16201681 is an equidigital number, since it uses as much as digits as its factorization.

16201681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 16201681 is about 4025.1311779866. The cubic root of 16201681 is about 253.0385512033.

The spelling of 16201681 in words is "sixteen million, two hundred one thousand, six hundred eighty-one".